Radeon HD 4770 vs Radeon HD 7870

Intro

Compare those specs to the Radeon HD 7870, which features core clock speeds of 1000 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 memory. It features 1280 SPUs along with 80 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 7870		175 Watts
	Difference: 95 Watts (119%)

Memory Bandwidth

The Radeon HD 7870 should in theory be quite a bit faster than the Radeon HD 4770 overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 102400 (200%)

Texel Rate

The Radeon HD 7870 is a lot (approximately 233%) more effective at AF than the Radeon HD 4770. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 56000 (233%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7870 is a better choice, by a large margin. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 20000 (167%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of information (measured in megabytes per second) that can be transported past the external memory interface in one second. It's worked out by multiplying the interface width by the speed of its memory. If it uses DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total number of texture units by the core speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.